trans-1,2-Dichloroethylene is a chlorinated solvent which has a boiling point of 48° C. and which, in the same way as trichloroethane, trichloroethylene and perchloroethylene, has a good solubilizing power, in particular for fatty substances (lubricants, oils, greases). Its use has to date been relatively limited because of the existence, for this solvent, of a flash point. trans-1,2-Dichloroethylene effectively has a flash point of between −11° C. and −4° C. under the standard determination conditions (Standard D3828-02: closed cup, Setaflash).
U.S. Pat. No. 3,349,039 discloses compositions based on trans-1,2-dichloroethylene and on 1,1,2-trifluoro-1,2,2-trichloroethane or on methylene chloride, the latter two compounds making it possible to suppress the flash point of trans-1,2-dichloroethylene. However, these mixtures are not really of interest now as 1,1,2-trifluoro-1,2,2-trichloroethane has been banned since the Montreal protocol and methylene chloride is strictly regulated (harmful Carcinogenic, Mutagenic and Reprotoxic substance).
U.S. Pat. No. 6,100,229 discloses compositions based on azeotropic trans-1,2-dichloroethylene and 1,1,1,3,3-pentafluoropropane mixtures but with a high content of 1,1,1,3,3-pentafluoropropane. The disadvantage of such a mixture is its relatively low boiling point, a value in the region of 20° C. for a composition comprising only 20% of trans-1,2-dichloroethylene.
Furthermore, the use of trans-1,2-dichloroethylene with a blowing agent in the manufacture of thermosetting polymer foams is known.
In many applications, the components of the polyurethane foams are premixes. More generally, the formulation of the foams is premixed as two components. The first component, better known under the name “component A”, comprises the isocyanate or polyisocyanate composition. The second component, better known under the name “component B”, comprises the polyol or the mixture of polyols, the surface-active agent, the catalyst or catalysts and the blowing agent or agents.
The “component B” presents problems of flammability, even when the blowing agent forming part of the composition of the premix is nonflammable.
In addition, problems of rise in pressure in the containers holding the “component B” are often encountered during their storage.